The union said working to rule and an overtime ban will begin on March 6, with tug masters, boat masters and barge masters set to take 24 hours of strike action on the same day.
Royal Navy tugboat and marine services crews, some of whom move nuclear submarines, are set to take strike action in March in a dispute over proposed contract changes.
Unite said its members are set to begin working to rule and an overtime ban on March 6, with different parts of the workforce also staging 24-hour strikes on March 6, 7 and 10.
Unite said 300 of its members at Devonport in Devon, Portsmouth in Hampshire, and at Faslane, Great Harbour Greenock and Kyle of Lochalsh in Scotland will walk out amid claims they are being locked out of consultations between their employer and the Royal Navy over the services they provide.
The crews are employed by Serco Marine, which the union said is currently in talks with the Ministry of Defence (MoD) about renewing its 10-year, £1.2 billion contract with the Royal Navy.
